MW & H2O Magazine February 2012

MW & H2O Magazine February 2012

THE PEAK EFFICIENCY OF
SOLAR-CELLS RANGES
BETWEEN 8- 17%, BUT THIS IS
NOT THE WHOLE PICTURE
r&d FEATURE
Prototype Creation takes a different approach to
reducing the use of fossil resources in dry land agriculture
with the IBTS desalination greenhouse. The invention of
this closed-loop system is equivalent to the invention of
high efficiency solar-cells or a biogas power plant with
unprecedented resource-productivity. Although embedded
energy in food is not on the radar of consumers (and other
base decision makers) as an alternative in the electrical
energy sector, it is the same on many levels. It is different
again, reminiscing that food-production is the beginning
of any economy. All subsequent products and services
are dependent on the uninterrupted functionality of food
provision.
The Integrated Biotectural System
Integrated Biotectural System (IBTS) is a broadband
solution for energy and water generation providing fresh
water from a highly saturated greenhouse atmosphere by
relying on solar power. The beauty of this utility lies not in
only its appearance, but in the proximity and linkage of all
the core elements of agriculture. None of the commodities
have to be imported once the water and nutrient cycles
are charged; on the contrary, the IBTS exhibits solar
desalination as means of charging the internal freshwater
cycle. The desalination feature continues to operate
after requirements of the greenhouse are met to produce
excess for export. The electrical energy requirement for the
condensation of the humid air is below 1.8kwh/m³ a new
efficiency record for desalination. The reason for this leap is
integration.
The low efficiency of photosynthesis with ~4% inside the
greenhouse can be compared to new solar-cells with 16%
conversion of solar irradiation. Inside the IBTS, all plants
act as water pumps and fine dispersers in addition to the
generation of bio energy. Principally, they offer the same
effect that energy intensive technology evaporation would
offer. The height of this effect occurs in the morning, when
solar irradiation and energy in the thermal storage of the
IBTS are down.
A truthful perspective
Photosynthesis is a process of converting sunlight into
useful energy embedded in a perfectly optimised system.
It is employed instead of cumbersome photovoltaic panels
and associated technology in greenhouses. The peak
efficiency of photosynthesis ranges between one per cent
and eight per cent but accumulates throughout the years of
growth and adoption to the environment. Each leaf on a tree
varies from the others with several dozen characteristics
in its capability to harness and convert sunlight . (6) Overly
high temperatures, which reduce the efficiency rates of
photosynthesis, as well as solar-cells, do not occur above
well-sized plantations. This valuable cooling effect is due
to integrated “services” like sunlight reflection or day-time
evaporation (from soil).
The peak efficiency of solar-cells ranges between eight
per cent and 17%, but this is not the whole picture because
they are high in investment compared to plantations. Life
cycle assessment (LCA) studies state their Energy Pay
Back Time or EPBT to lie between 1 to 4.5 years, (7,8,9)
but the energy required to build the production plants is not
accounted for. This would about double the time because
the EPBT of plants is three to four times higher than that of
modules (10).
Imagine that each unit of energy a PV module produces
is actually three units of energy because it substitutes
fossil energy sources that lose two thirds of their primary
energy when converted to electrical energy. Without this
assumption, the EPBT is about three times longer. In reality,
the fossil resources were only used to generate the solarcells. The power they generate is additional electricity. As
the installed capacity of new solar plants increases each
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